It is a known custom to apply at the centre of the steering wheel of cars and other motorvehicles an emblem, or like (usually the badge of the car factory or a logo relating to the type of motorvehicle), reproduced onto a badge-plate.
In the past, said application has never created any kinds of problems and has been accomplished in the most different ways, always using besides very plain and simple means.
Things have been changing with the more and more frequent introduction, in motorvehicles, of the so-called "air bag" safety devices, which are usually positioned into a housing associated to the vehicle steering wheel.
As known, the central portion of the front wall of said housing--usually consisting of reinforced plastic material--is meant to brake and open up with a violent blow at the moment in which the air bag device starts to operate: for this purpose, an undercut facilitating breakage is provided on three sides of a portion of said wall, which portion thus gets lifted--separating from said three sides and remaining anchored with its fourth side to the housing--to allow the outlet of the air bag.
Upon breaking, said wall portion and the portions connected thereto or any elements applied thereon--as for example the badge-plate usually positioned at the centre of the steering wheel--are sujected to very high stresses, mainly determined by the strong accelerations developing in opposite senses. Such stresses may then easily lead the badge-plate to break off from the wall portion just opened up and, though light and of small dimensions, said badge-plate could turn into a dangerous bullet.
To avoid risks of this kind, the use of badge-plates at the centre of steering wheels equipped with air bag devices is now-a-days allowed only if such plates are applied with a system tested so as to guarantee--when the air bag device starts to operate--that the badge-plate remains anchored to the wall housing the device, and to positively exclude its breaking off from said wall.
The problem has been faced and efficiently solved by the Applicant in the FR-9604121, which supplies a unit consisting of a badge-plate and a counterplate, wherein the badge-plate is formed by coining from a metal sheet, in one piece with at least a central projecting extruded pin having a conical cavity at its free end, and wherein the counterplate comprises a hole in correspondence of said pin and is steadily associated to the badge-plate--after having interposed between them the wall housing the air bag device--by riveting with a caulking the end of said pin of the badge-plate onto the edge of said hole of the counterplate.